Neutrophilia is an increase in the absolute neutrophil count in the peripheral circulation. Normal blood values vary by age. Neutrophilia can be caused by a direct problem with blood cells (primary disease). It can also occur as a consequence of an underlying disease (secondary). Most cases of neutrophilia are secondary to inflammation.

Primary causes

- Conditions with normally functioning neutrophils – hereditary neutrophilia, chronic idiopathic neutrophilia

- Pelger–Huet anomaly

- Down syndrome

- Leukocyte adhesion deficiency

- Familial cold urticaria

- Leukemia (chronic myelogenous (CML)) and other myeloproliferative disorders

- Surgical removal of spleen

Secondary causes

- Infection

- Chronic inflammation – especially juvenile rheumatoid arthritis, rheumatoid arthritis, Still's disease, Crohn's disease, ulcerative colitis, granulomatous infections (for example, tuberculosis), and chronic hepatitis

- Cigarette smoking – occurs in 25–50% of chronic smokers and can last up to 5 years after quitting

- Stress – exercise, surgery, general stress

- Medication induced – corticosteroids (for example, prednisone, β-agonists, lithium)

- Cancer – either by growth factors secreted by the tumor or invasion of bone marrow by the cancer

- Increased destruction of cells in peripheral circulation can stimulate bone marrow. This can occur in hemolytic anemia and idiopathic thrombocytopenic purpura

Neutropenia can be acquired or intrinsic. A decrease in levels of neutrophils on lab tests is due to either decreased production of neutrophils or increased removal from the blood. The following list of causes is not complete.

- Medications - chemotherapy, sulfas or other antibiotics, phenothiazenes, benzodiazepines, antithyroids, anticonvulsants, quinine, quinidine, indomethacin, procainamide, thiazides

- Radiation

- Toxins - alcohol, benzenes

- Intrinsic disorders - Fanconi's, Kostmann's, cyclic neutropenia, Chédiak–Higashi

- Immune dysfunction - disorders of collagen, AIDS, rheumatoid arthritis

- Blood cell dysfunction - megaloblastic anemia, myelodysplasia, marrow failure, marrow replacement, acute leukemia

- Any major infection

- Miscellaneous - starvation, hypersplenism

Symptoms of neutropenia are associated with the underlying cause of the decrease in neutrophils. For example, the most common cause of acquired neutropenia is drug-induced, so an individual may have symptoms of medication overdose or toxicity.

Treatment is also aimed at the underlying cause of the neutropenia. One severe consequence of neutropenia is that it can increase the risk of infection.

In some cancers, such as melanoma and colorectal cancer, lymphocytes can migrate into and attack the tumor. This can sometimes lead to regression of the primary tumor.

Langhans giant cells (also known as Pirogov-Langhans cells) are large cells found in granulomatous conditions.

They are formed by the fusion of epithelioid cells (macrophages), and contain nuclei arranged in a horseshoe-shaped pattern in the cell periphery.

Although traditionally their presence was associated with tuberculosis, they are not specific for tuberculosis or even for mycobacterial disease. In fact, they are found in nearly every form of granulomatous disease, regardless of etiology.

Plasma cells, also called plasma B cells, plasmocytes, plasmacytes, or effector B cells, are white blood cells that secrete large volumes of antibodies. They are transported by the blood plasma and the lymphatic system. Plasma cells originate in the bone marrow; B cells differentiate into plasma cells that produce antibody molecules closely modelled after the receptors of the precursor B cell. Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction.

Plasmacytoid dendritic cells (pDCs) are innate immune cells that circulate in the blood and are found in peripheral lymphoid organs. They develop from bone marrow hematopoietic stem cells and constitute < 0.4% of peripheral blood mononuclear cells (PBMC).

In humans they exhibit plasma cell morphology and express CD4, HLA-DR, CD123, blood-derived dendritic cell antigen-2 (BDCA-2), Toll-like receptor (TLR) 7 and TLR9 within endosomal compartments, but do not express high levels of CD11c or CD14, which distinguishes them from conventional dendritic cells or monocytes, respectively. Mouse pDC express CD11c, B220, BST-2/Tetherin (mPDCA) and Siglec-H and are negative for CD11b.

As components of the innate immune system, these cells express intracellular Toll-like receptors 7 and 9 which detect ssRNA and unmethylated CpG DNA sequences, respectively. Upon stimulation and subsequent activation, these cells produce large amounts (up to 1,000 times more than other cell type) of type I interferon (mainly IFN-α (alpha) and IFN-β (beta)), which are critical pleiotropic anti-viral compounds mediating a wide range of effects.

The number of circulating pDCs are found to be decreased during chronic HIV infection as well as HCV infection.

A lymphocyte is one of the subtypes of white blood cell in a vertebrate's immune system. Lymphocytes include natural killer cells (Phagocytes) (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic adaptive immunity), and B cells (for humoral, antibody-driven adaptive immunity). They are the main type of cell found in lymph, which prompted the name "lymphocyte".

Langhans cells are often found in transbronchial lung biopsies or lymph node biopsies in patients suffering from sarcoidosis.

Basophils are a type of white blood cells. Basophils are the least common of the granulocytes, representing about 0.5 to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammatory reactions during immune response, as well as in the formation of acute and chronic allergic diseases, including anaphylaxis, asthma, atopic dermatitis and hay fever. They can perform phagocytosis (cell eating), produce histamine and serotonin that induce inflammation, and heparin that prevents blood clotting. It used to be thought that basophils that have migrated from blood into their resident tissues (connective tissue) are known as mast cells, but this is no longer thought to be the case.

Basophils were discovered in 1879 by German physician Paul Ehrlich, who one year earlier had found a cell type present in tissues that he termed "mastzellen" (now mast cells). Ehrlich received the 1908 Nobel Prize in Physiology or Medicine for his discoveries.

The name comes from the fact that these leukocytes are basophilic, i.e., they are susceptible to staining by basic dyes, as shown in the picture.

The Xanthogranulomatous Process (XP), also known as Xanthogranulomatous Inflammation is a form of acute and chronic inflammation characterized by an exuberant clustering of foamy macrophages among other inflammatory cells. Localization in the kidney and renal pelvis has been the most frequent and better known occurrence followed by that in the gallbladder but many others have been subsequently recorded. The pathological findings of the process and etiopathogenetic and clinical observations have been reviewed by Cozzutto and Carbone.

The 5 year survival has been noted as 89% in at least one study from France of 201 patients with T-LGL leukemia.

Dendritic cells (DCs) are antigen-presenting cells (also known as "accessory cells") of the mammalian immune system. Their main function is to process antigen material and present it on the cell surface to the T cells of the immune system. They act as messengers between the innate and the adaptive immune systems.

Dendritic cells are present in those tissues that are in contact with the external environment, such as the skin (where there is a specialized dendritic cell type called the Langerhans cell) and the inner lining of the nose, lungs, stomach and intestines. They can also be found in an immature state in the blood. Once activated, they migrate to the lymph nodes where they interact with T cells and B cells to initiate and shape the adaptive immune response. At certain development stages they grow branched projections, the "dendrites" that give the cell its name (δένδρον or déndron being Greek for "tree"). While similar in appearance, these are structures distinct from the dendrites of neurons. Immature dendritic cells are also called veiled cells, as they possess large cytoplasmic 'veils' rather than dendrites.

Memory T cells are a subset of infection- and cancer-fighting T cells (also known as a T lymphocyte) that have previously encountered and responded to their cognate antigen; thus, the term antigen-experienced T cell is often applied. Such T cells can recognize foreign invaders, such as bacteria or viruses, as well as cancer cells. Memory T cells have become "experienced" by having encountered antigen during a prior infection, encounter with cancer, or previous vaccination. At a second encounter with the invader, memory T cells can reproduce to mount a faster and stronger immune response than the first time in the immune system responded to the pathogen which is entered into the body. This behaviour is utilized in T lymphocyte proliferation assays, which can reveal exposure to specific antigens.

The lymphoma is more common in the young and in males.

A 2008 study found an increased risk of ALCL of the breast in women with silicone breast implants (protheses), although the overall risk remained exceedingly low due to the rare occurrence of the tumor.

Histologic transformation to diffuse large B-cell lymphoma (DLBCL) can occur in up to 12% of cases. After transformation, neoplastic cells carry monoclonal immunoglobulin gene rearrangements. Histological transformation may lead to poor prognosis and therefore repeat biopsy is required at relapse.

One study found a transformation rate of 7.6%, and suggested that prior exposure to chemotherapy and a presentation with splenic involvement were associated with increased risks of transformation.

T-LGLL is a rare form of leukemia, comprising 2-3% of all cases of chronic lymphoproliferative disorders.

One study has suggested improved overall survival in response to chemotherapy for African Americans.

Plasmacytoma, multiple myeloma, Waldenström macroglobulinemia and plasma cell leukemia are malignant neoplasms ("cancer") of the plasma cells. Multiple myeloma is frequently identified because malignant plasma cells continue producing an antibody, which can be detected as a paraprotein.

Common variable immunodeficiency is thought to be due to a problem in the differentiation from lymphocytes to plasma cells. The result is a low serum antibody level and risk of infections.

Primary amyloidosis (AL) is caused by the deposition of excess immunoglobulin light chains which are secreted from plasma cells.

Of all cancers involving the same class of blood cell (lymphoproliferative disorders), 22% of cases are follicular lymphomas.

A second regimen under evaluation is R-EPOCH (rituximab with etoposide-prednisone-vincristine-doxorubicin-cyclophosphamide), which demonstrated a 5-year progression-free survival (PFS) of 79% in a phase II trial. A phase III trial, CALGB 50303, is now comparing R-EPOCH with R-CHOP in patients with newly diagnosed DLBCL.

One area of active research is on separating patients into groups based on their prognosis and how likely they are to benefit from different drugs. Methods like gene expression profiling and next-generation sequencing may result in more effective and more personalized treatment.

The xanthogranulomatous type of inflammation is most-commonly seen in pyelonephritis and cholecystitis, although it has more recently been described in an array of other locations including bronchi, lung, endometrium, vagina, fallopian tubes, ovary, testis, epydidymis, stomach, colon, ileum, pancreas, bone, lymph nodes, bladder, adrenal gland, abdomen and muscle. Telling apart clinically a XP from a tumor condition can be challenging as pointed out by several authors. Cozzutto and Carbone suggested that a wide array of entities characterized by a large content of histiocytes and foamy macrophages could be traced back at least in part to a xanthogranulomatous inflammation. These include such varied disturbances as xanthoma disseminatum, ceroid granuloma of the gallbladder, Whipple's disease, inflammatory pseudotumor of the lung, plasma cell granuloma of the lung, malakoplakia, verruciform xanthoma, foamy histiocytosis of the spleen in thrombocytopenic purpura, isolated xanthoma of the small bowel, xanthofibroma of bone, and gastric xanthelasma.

A pathogenetic model might be suggested as follows:

1. suppuration, hemorrhage and necrosis,

2. granulomatous tissue with granular histiocytes and foamy macrophages,

3. fibrohistiocytoma-like or plasma cell granuloma-like patterns,

4. possible myofibroblast metaplasia.

A reactive fibrohistiocytic lesion simulating fibrous histiocytoma has been reported by Snover et al. Reactive granular cells in sites of trauma have been regarded of histiocytic nature. Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) might share several aspects of the XP. Likewise there might be some superimpositions between the XP and the plasma cell granuloma/histiocytoma-inflammatory myofibroblastic tumor complex.> The XP might be an important stage of this complex.

Of all cancers involving the same class of blood cell, 8% of cases are MALT lymphomas.

The prognosis varies according with the type of ALCL. During treatment, relapses may occur but these typically remain sensitive to chemotherapy.

Those with ALK positivity have better prognosis than ALK negative ALCL. It has been suggested that ALK-negative anaplastic large-cell lymphomas derive from other T-cell lymphomas that are morphologic mimics of ALCL in a final common pathway of disease progression. Whereas ALK-positive ALCLs are molecularly characterized and can be readily diagnosed, specific immunophenotypic or genetic features to define ALK-negative ALCL are missing and their distinction from other T-cell non-Hodgkin lymphomas (T-NHLs) remains controversial, although promising diagnostic tools for their recognition have been developed and might be helpful to drive appropriate therapeutic protocols.

Systemic ALK+ ALCL 5-year survival: 70–80%.

Systemic ALK- ALCL 5-year survival: 15–45%.

Primary Cutaneous ALCL: Prognosis is good if there is not extensive involvement regardless of whether or not ALK is positive with an approximately 90% 5-year survival rate.

Breast implant-associated ALCL has an excellent prognosis when the lymphoma is confined to the fluid or to the capsule surrounding the breast implant. This tumor can be recurrent and grow as a mass around the implant capsule or can extend to regional lymph nodes if not properly treated.

James Cerhan and colleagues, try to determine genetic susceptibility that exists for this cancer by meta-analysis of three genome-wide association studies (GWAS). For this, a total of 3,857 cases and 7,666 controls were analyzed. This study is divided into three stages, which can differentiate into two phases:

– Discovery Phase: Stages 1 and 2.

– Phase replication: Stage 3.

Basophils contain large cytoplasmic granules which obscure the cell nucleus under the microscope when stained. However, when unstained, the nucleus is visible and it usually has two . The mast cell, another granulocyte, is similar in appearance and function. Both cell types store histamine, a chemical that is secreted by the cells when stimulated. However, they arise from different branches of hematopoiesis, and mast cells usually do not circulate in the blood stream, but instead are located in connective tissue. Like all circulating granulocytes, basophils can be recruited out of the blood into a tissue when needed.